1. Field of the Invention
The present disclosure relates to an image heating apparatus mounted on an electrophotographic image forming apparatus such as a copying machine and a printer.
2. Description of the Related Art
Generally, an image heating apparatus mounted on an electrophotographic image forming apparatus such as a copying machine and a printer heats a toner image formed on a recording material while conveying the recording material bearing the unfixed toner image at a nip portion formed by a rotatable member and a pressure roller in pressure contact with the rotatable member.
In recent years, there has been proposed an image heating apparatus according to the electromagnetic induction heating method that allows a conductive layer included in the rotatable member to directly generate heat. This image heating apparatus according to the electromagnetic induction heating method has advantages of being able to warm up in a short time, and consuming only low power. Japanese Patent Application Laid-Open No. 2004-61998 discusses a fixing apparatus that includes a rotatable member containing therein an exciting coil and a magnetic core divided into a plurality of pieces, and supplies a current to the coil to produce an alternative magnetic field to thereby cause the rotatable member to generate heat by Joule heat derived from an eddy current flowing on the rotatable member.
However, when a plurality of magnetic cores is arranged in a generatrix direction of the rotatable member, like Japanese Patent Application Laid-Open No. 2004-61998, in the rotatable member, an amount of generated heat may be reduced at a position of the rotatable member corresponding to a division region between the magnetic cores to generate uneven heat, causing an image defect.